Amazon Basics Rubber Encased Hex Dumbbell Hand Weight (various weight) from $22.39

Dumbbell for resistance training—great for arms, chest, back, core, and legs
Solid cast-iron core for reliable strength; will not bend or break after repeated use
Hexagon-shaped rubber-encased ends help prevent rolling and promote stay-in-place storage
Contoured, textured, chrome handle for a comfortable, secure grip
Sold individually; weighs 20 pounds